This invention relates generally to control valves, and more particularly to chokes which serve to dissipate the energy of high pressure fluid, as for example fluid rising from a well.
Choke valves are commonly connected to the well annulus at the well surface to dissipate the energy of high pressure fluid. During drilling, such fluid may entrain small particles including drill cuttings loosened from the underground formation. During well production the produced fluid may consist of petroleum, or gas under pressure, and containing smaller amounts of abrasive. The fluid may under other conditions consist of high pressure steam, as during a period of stem injection into the well to increase hydrocarbon flow. These and other varied conditions of fluid flow require the use of different types of chokes, i.e. choke valves especially adapted to best handle the particular fluids rising from the well.
In the past, it was necessary to disconnect the choke valve including the valve body from the well head riser pipe, and replace it with the different choke valve selected for the type of fluid flow encountered. This required an inventory of several choke valves, at or near the well site, which was relatively expensive. Also, the disconnection and connection of the choke valve bodies from and to the well riser pipes, as well as to and from fluid discharge piping, was time consuming, unwieldy and sometimes dangerous.